Within the prior art, the problems of protecting personal or proprietary information have become increasingly important. Indeed, as the concepts of E-commerce have become more and more prevalent, the manner in which the proprietary or personal information is illegally obtained has increased. This is not only true of E-commerce being conducted over the Internet but also on Intranets within a commercial, governmental, or academic environment. One method that is used to obtain personal or proprietary information is the use of “keyboard-sniffers”. Keyboard-sniffers are software or hardware based intrusions (also referred to as “bugs”) that secretly record every keystroke on a computer and transmit/record it for later use by a third party who is illicitly gathering information. A keyboard-sniffer circumvents most password-protected encryption systems, by obtaining the personal or proprietary information before it can be encrypted. Software-based keyboard-sniffers can be manually installed on a computer system or may take the form of “virus” infestations being received from a network such as the Internet or Intranet.
One technique to protect against keyboard-sniffers is to attempt to prevent keyboard-sniffers from being installed in the first place. This attempt suffers from the problem that the software techniques utilized to insert sniffers/viruses into computer systems are constantly evolving. In addition, hardware based keyboard-sniffers can be installed on an unattended computer in only a couple of minutes since all that is necessary is to simply insert a small device between the keyboard and the computer. Also, with the growing number of wireless keyboards, it is not necessary to physically insert hardware between the keyboard and the computer. With respect to wireless keyboards, all that is necessary is to locate a receiver within the transmission range of the wireless keyboard.
A second technique that the prior art has attempted to utilize to circumvent keyboard-sniffers is to display numbers and letters on the console of a computer and have the user utilize the mouse to point out the password by touching various numbers and letters on the console screen.
A third technique that has been utilized by some password and entry programs is to display on the console screen randomized character mapping for a user to perform on their own password before the user enters the password.
A fourth technique is to insert a hardware device into a link interconnecting a keyboard and a computer. The hardware device automatically generates a different password each time the user logs onto the computer or a server via the computer. (See the application note entitled “Using KeeLoq to Generate Hopping Passwords”. Application note AN665, Microchip Technology, Inc., 1997). These prior art techniques suffer from many problems including human factors, implementation, and limited use.